SCOTTSDALE, Ariz. -- The D-backs' stock of mound prospects begins with Archie Bradley, the best in the game. But it doesn't come anywhere close to stopping there.

The strength of Arizona's farm system is pitching, even after trading Trevor Bauer, Tyler Skaggs and David Holmberg since the end of the 2012 season.

Beyond Bradley, there's Braden Shipley and Aaron Blair, whose combination of polish and stuff led the franchise to grab them with its top two picks in the 2013 Draft. Jose Martinez has yet to reach full-season ball, but he can light up radar guns better than anyone in the organization, including Bradley. Zeke Spruill isn't as sexy, but he is ready to contribute in the Major Leagues.

"We've got some really good arms and good starting pitching," D-backs farm director Mike Bell said. "Archie is knocking on the door and he gets better each time you see him. Shipley, what an athlete, he's really fun to watch pitch. Blair is very steady and Martinez has plenty of arm strength."

And those are just the starters. Arizona may have more quality relief prospects than any system.

The best are Matt Stites and Jake Barrett, who are on the verge of arriving at Chase Field, as are Kevin Munson and Evan Marshall. Stites was acquired in the Ian Kennedy trade with the Padres last summer, while Munson just rejoined the organization after the Phillies selected him in the Rule 5 Draft. In last year's Draft, the D-backs found two more college arms who should move quickly through the Minors in bullpen roles in Jimmie Sherfy and Daniel Gibson.

"We have relievers top to bottom at each level," Bell said. "They're power arms who throw strikes. We have a lot of options for K.T. [GM Kevin Towers] and the big league staff."

While the pitchers take center stage, the system isn't bereft of hitters. Chris Owings, the Triple-A Pacific Coast League MVP, is about to win Arizona's shortstop job. Like Owings, many of the D-backs' best position prospects play on the left side of the infield, including third basemen Jake Lamb and Brandon Drury, and shortstop Sergio Alcantara.

Three questions with Stites

Since signing with the Padres for $45,000 as a 17th-round pick in 2011, Stites has put up spectacular numbers in the Minors: a 1.53 ERA, 150/19 K/BB ratio in 135 1/3 innings and a .159 opponent average. The only thing that has slowed down the 5-foot-11 right-hander was a midseason appendectomy last July, four days before San Diego traded him, Joe Thatcher and a supplemental second-round choice for Kennedy.

MLBPipeline.com: Could the end of July last year have been any more eventful for you?

Stites: That was the weirdest four days of my life. I woke up one day with what I thought was just a stomach ache, and then I thought it was just a tight muscle that I figured would straighten itself out. Luckily, my girlfriend was there, and the next morning I went to the hospital and was told I was going to have surgery that day. I was there for four days, and when I got discharged I went to the medicine shop at the hospital. [Padres GM] Josh Byrnes called to check how I was feeling, then told me I had been traded. I was excited and shocked, but I was also still in pain.

MLBPipeline.com: You participated in your first big league camp this spring. What was that like?

Stites: The biggest difference is that in a Minor League Spring Training game, there's only about seven people there versus thousands over there. I got into three games, including one against the Angels. I'm from St. Louis and watched him growing up, so facing Albert Pujols was fun. I threw him a 1-1 fastball and tried to go away, but [the pitch] got the middle of the plate. He got it and singled up the middle. He generally gets those.

MLBPipeline.com: Your velocity has consistently increased: from 88-94 mph in junior college, to 90-95 at Missouri, to 92-96 in your first year of pro ball, to 94-98 last season. How did that happen?

Stites: Moving to the bullpen really helped me velocity-wise. I couldn't start in pro ball. Those guys have three good pitches and I only have two. I put on 13 pounds in my first year in pro ball. I noticed a velocity uptick in Spring Training, and it took off from there. Workouts have helped a lot, too. The strength and conditioning coaches here are tremendous.

The D-backs drafted Trahan 26th overall in 2012, signing him out of a Louisiana high school for $1.7 million. He has spent the first two years of his career in Rookie ball, batting a combined .266/.370/.467 with 15 homers in 108 games.

Trahan's standout tool always has been his big left-handed power, and scouts have had mixed opinions on his ability to stay behind the plate. He has a strong arm, but his receiving and agility have a long way to go, as evidenced by his 35 passed balls in 84 games as a catcher.

To expedite the development of Trahan's bat, Arizona has decided to make him a corner outfielder. The Nationals did the same thing with Bryce Harper, as did the Royals with Wil Myers prior to trading him to the Rays. Bell said Trahan, 19, has looked good offensively and defensively.

"His bat was ahead of his defense, and we didn't want to hold him back," Bell said. "He needs to get out of Rookie ball, and this gave him a better chance. He looks comfortable in the outfield and keeps getting more comfortable. He's moving well out there. You watch him in batting practice and he's impressive, and he's done it in games, too."

Breakout candidate: Martinez

There's something about small Dominican right-handers named Martinez who throw hard. Jose is a few years away from being ready for the Majors, but his fastball is reminiscent of those of Pedro and Carlos Martinez. (None of them are related to each other.)

Though he's just 6-foot-1 and 160 pounds, Martinez has an exceptionally quick arm. Signed for $55,000 out of the Dominican Republic in 2011, he worked with a mid-90s fastball last summer in the short-season Northwest League, where he limited opponents to a .159 average. Martinez has dialed up even more heat this spring.

"He's starting to get stronger and more confident," Bell said. "He was up to 98-99 mph the other day. He has a plus curveball and his changeup is coming. He's young and he's still developing."

Martinez will have to prove that his slim frame can endure the rigors of a full season, and he'll have to upgrade his control and command as well. But his arm could make him a front-line starter or a closer, and the D-backs are excited to see what he'll do this year at low Class A South Bend.

Jim Callis is a reporter for MLB.com and writes a blog, Callis' Corner. Follow @jimcallisMLB on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.